In the latter case, a free parameter in the DM sector of the
Lagrangian is the Wino mass and the cross section is determined
uniquely for a given Wino mass. Besides, the Wino mass is determined
to be 2.7–3 TeV if the thermal freeze-out scenario is assumed. We
have computed the Wino annihilation cross section at the
next-to-leading log level following Ref. [1]} and
derived the current limits on the annihilation cross section and the
future sensitivity by CTA observation. It has been found that
measurements of one of the ultrafaint dSphs (Reticulum, Segue 1, and
Ursa Major II) and classical dSphs (Draco and Ursa Minor) will give us
sufficient sensitivity to detect the Wino DM with 2.7–3 TeV mass with
CTA observations for 500 hours. This conclusion is nearly independent
of the priors, thus it is a robust prediction. One should, however,
keep in mind relatively large uncertainties related to the density
profile estimates of Segue 1 ultrafaint dSph, when making a decision
on which of these dSphs should be chosen as the best target. We
conclude that observing dSphs is another powerful tool to detect the
Wino DM as well as the observation of the Galactic center region.
